diff --git a/tools/viewer/NIMASlide.cpp b/tools/viewer/NIMASlide.cpp
index 4d094c4..c1a3356 100644
--- a/tools/viewer/NIMASlide.cpp
+++ b/tools/viewer/NIMASlide.cpp
@@ -341,6 +341,10 @@
 
 NIMASlide::~NIMASlide() {}
 
+SkISize NIMASlide::getDimensions() const {
+    return SkISize::MakeEmpty(); // TODO
+}
+
 void NIMASlide::draw(SkCanvas* canvas) {
     canvas->save();
 
diff --git a/tools/viewer/NIMASlide.h b/tools/viewer/NIMASlide.h
index b4d5d2b..d1b1298 100644
--- a/tools/viewer/NIMASlide.h
+++ b/tools/viewer/NIMASlide.h
@@ -31,6 +31,8 @@
     NIMASlide(const SkString& name, const SkString& path);
     ~NIMASlide() override;
 
+    SkISize getDimensions() const override;
+
     void draw(SkCanvas* canvas) override;
     void load(SkScalar winWidth, SkScalar winHeight) override;
     void unload() override;
diff --git a/tools/viewer/SampleSlide.cpp b/tools/viewer/SampleSlide.cpp
index 13597f7..9b1737a 100644
--- a/tools/viewer/SampleSlide.cpp
+++ b/tools/viewer/SampleSlide.cpp
@@ -23,6 +23,10 @@
 
 SampleSlide::~SampleSlide() { delete fClick; }
 
+SkISize SampleSlide::getDimensions() const  {
+    return SkISize::Make(SkScalarCeilToInt(fSample->width()), SkScalarCeilToInt(fSample->height()));
+}
+
 void SampleSlide::draw(SkCanvas* canvas) {
     SkASSERT(fSample);
     fSample->draw(canvas);
diff --git a/tools/viewer/SampleSlide.h b/tools/viewer/SampleSlide.h
index ec5253a..7cf1d3c 100644
--- a/tools/viewer/SampleSlide.h
+++ b/tools/viewer/SampleSlide.h
@@ -16,6 +16,8 @@
     SampleSlide(const SampleFactory factory);
     ~SampleSlide() override;
 
+    SkISize getDimensions() const override;
+
     void draw(SkCanvas* canvas) override;
     void load(SkScalar winWidth, SkScalar winHeight) override;
     void resize(SkScalar winWidth, SkScalar winHeight) override {
diff --git a/tools/viewer/Slide.h b/tools/viewer/Slide.h
index 023cd6b..a2ee307 100644
--- a/tools/viewer/Slide.h
+++ b/tools/viewer/Slide.h
@@ -21,9 +21,7 @@
 public:
     virtual ~Slide() {}
 
-    virtual SkISize getDimensions() const {
-        return SkISize::Make(0, 0);
-    }
+    virtual SkISize getDimensions() const = 0;
 
     virtual void draw(SkCanvas* canvas) = 0;
     virtual bool animate(const SkAnimTimer&) { return false;  }